Non-toxic biodegradable linear poly (ester-urethane-urea)s with different hydrophilic character were synthesized from poly(F-caprolactone) as macrodiol, L-lysine diisocyanate (LDI) and ethyl ester L-lysine or L-ornithine as chain extenders. Linear segmented polymers were synthesized by the prepolymer method with a tertiary amine playing a critical role in the chain extension in heterogeneous conditions. The prepared segmented polymers were fully chemically and physically characterized, including water uptake and hydrolytic stability measurements. Depending on the poly(epsilon-caprolactone) length, the segmented polymers were amorphous or semicrystalline. The crystallinity degree strongly affected the mechanical properties and water uptake behaviour. (c) 2005 Elsevier Ltd. All rights reserved.